Farmers of livestock such as sheep, goats, pigs and cattle need to record information about each animal. The information recorded depends on the needs of each farmer. Thus the records needs of a wool farmer differ from those of a farmer breeding sheep for meat.
Conventionally an animal is fitted with an eartag to which a serial number is applied. The animal's pedigree, age, breeding record, wool production etc is then recorded either in a computer or in ledgers in the farmer's office. The serial number links the animal to the record.
The difficulty with this system is that once an animal has been located and its serial number read, the farmer must then return to his office to find out anything about the animal in question. This is a tedious procedure and the animal must then be located again in the herd if action is to be taken based on the information found in the record.